FG Aufbereitungstechnik und Sekundärrohstofftechnologie (ehemals)
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Together with industrial partners, a complex apparatus was developed at the Brandenburg Technical University Cottbus-Senftenberg, which can be used to decoat gold-bearing waste from PCB- produc-tion waste and contact stripes using biotechnological methods. As a result, a complete and separate recovery of the gold flakes and the carrier material copper with high purity is possible. The bioleaching process is done with iron and sulfur oxidizing bacteria, especially Acidithiobacillus ferrooxidans, Leptospirilum ferrooxidans and Acidithiobacillus thiooxidans. Compared to processes using inorganic acids, shorter leaching times can be achieved, partial regenera-tion and multiple use of the bioleaching solution is possible (more than 10 times with the same leach-ing solution). After optimizing the conditions a process time of only 60 hours was reached. The sepa-rated gold tinsel with a content of over 900 mg/g Au is then fed into a precious metal smelter. Due to the biological leaching and the resulting concentration of the gold components, only < 1 wt.% of the waste containing precious metals has to be thermally treated.
Automotive technology is increasingly determined by electric vehicles driven by high-performance lithium ion batteries (LIB). Li-ion batteries equipped with layered oxide cathodes, which are constituted by oxides of nickel, manganese and cobalt, are proven as storage devices that combine high electrical power, high cycling stability and compact dimensions. These batteries contain large amount of valuable elements, such as the cathodes consisting of cobalt and nickel, the electrode carrier foils consisting of copper and aluminium. Therefore, spent LIB’s are valuable secondary resources.
Thermal processing as the classical recycling-technology for LIB’s is energy-intensive and allow only a partial recovery of some value elements.
Scientists of the Brandenburg University of Technology (Germany) developed in collaboration with industrial partners (SME) a process, in which the complex system LIB is partly automated dismounted into its basic components. The core of this process is the separation of anodes and cathodes from each other and an almost complete recovery of the cathode material from the foil.
The recovered cathode material has an enormous potential for a re-use in new LIB’s. By a proper combination of separation and post-treatment the material has a quality that is close to virgin cathode material. Preliminary studies made on LIB’s containing a fraction of recycled cathode material up to 50% show an electrical performance comparable to LIB’s made from virgin material.
Rückgewinnung und Aufbereitung der Kathodenbeschichtungen von Lithium-Ionen-Traktionsakkumulatoren
(2019)
Die energie- und ressourcenschonende Aufbereitung von End-of-life-Lithium-Ionenakkus ist ein gesellschaftliches und wirtschaftliches Erfordernis, da mit dem zunehmenden Einsatz von Elektrofahrzeugen die Zahl von ausgedienten oder defekten Li-Traktionsbatterien zunehmen wird. Die klassische Aufbereitung dieser Akkus, insbesondere mit Hochtemperaturverfahren, ist energetisch aufwändig und führt zudem nur zur partiellen Rückgewinnung der Wertelemente, die dann auch erst durch weitere mechanische und chemische Prozesse wieder zu verwendbaren Materialien werden.
Die vom Fachgebiet Aufbereitungstechnik der BTU mit verschiedenen Industriepartnern seit 2010 entwickelte Technologie verfolgt einen grundlegend anderen Ansatz. Ausgehend von einer hoch mechanisierten und teilweise automatisierten Demontage der Akkus können dabei die Einzelkomponenten weitgehend unzerstört und ohne thermische Schädigung oder Verlust brennbarer und leicht flüchtiger Anteile zurück gewonnen werden.
Für die Abtrennung der Kathodenbeschichtung von der Trägerfolie kommt nach der Zellendemontage eine hoch mechanisierte Nassaufbereitung zum Einsatz, bei der mittlerweile vollständig auf den Einsatz von Chemikalien verzichtet werden kann. Das separierte NMC-Schwarzmaterial soll so aufbereitet werden, dass es zukünftig in Recyclat-Zellen für verschiedene Anwendungen genutzt werden kann. Dazu werden verschiedene Zerkleinerungs- und Sortiertechnologien getestet.
The treatment of iron-hydroxide-containing water from ground water and surface water is achieved by a combination of the process steps of flocculation and subsequent mechanical dewatering. The aim is to create solid pellet structures by extending the structure forming flocculation process with a build-up pelletizing process which can be transferred directly into a drying unit. A Taylor-Couette-reactor (diameter of the inner cylinder – 40 mm, gap width – 5 mm) was used for these experimental studies. To produce the necessary flow profile the inner cylinder was rotated at a speed of 230 rpm. The iron hydroxide-containing suspension (dry matter content: 2 mass %) was added simultaneously with the addition of a cationic high-molecular flocculant in various flocculant dosages and residence times of 5 to 15 min. The pellets were examined for parameters such as geometric dimensions, dry substance content and dewatering behaviour. As the results show, there is a direct relationship between the residence time and the geometric dimensions of the pellets. After a residence time of 5 min, round pellets with an average diameter of 6 mm were formed. With an increase in the residence time up to 15 min, a compaction of the pellets could be observed, which resulted in an increase in the dry substance content of 8.0 to 11.2 mass % on average. After completion of the pelletizing process, the pellets were mechanically dewatered by filtration. By applying this innovative wet pelletizing of iron-hydroxide containing suspensions in a Taylor-Couette-reactor, it is possible to carry out the process of flocculation combined with the pellet formation with simultaneous pellet compaction in a single process step. The resulting pellet structures are distinguished from conventional floc structures by an improved water discharge capacity. After classification the pellets can be marked directly as easy-to-handle bulk material, suitable as feedstock in percolation columns for the purification of contaminated fluid streams
A mathematical model for the prediction of phase change temperatures and crystallization paths for mixtures consisting of palmitic (P), stearic (S), oleic (O), linoleic (L) and linolenic acid (Ll) in any distribution is presented in this paper. This model is based on the information gathered from modeled ternary phase diagrams, namely PSO, PSL, PSLl and OLLl, that were based on experimental binary phase diagrams of all possible combinations of these fatty acids. These experimental binary phase diagrams were obtained by means of differential scanning calorimetry and mathematical function fitting, within which the eutectic region of binary palmitic/stearic with oleic/linoleic/linolenic acid was investigated in detail. The basic mathematical model used was previously shown in literature which delivered good results for such systems. The importance of the developed model was then justified by investigations on real and composed synthetic fatty acid mixtures, where a high accuracy of the predicted temperatures could be shown for the technically relevant liquidus and solidus temperatures. A satisfying prediction for thermal events below the first solidus line could be reached as well. This work directly contributes to an enhanced understanding of the thermodynamic and kinetic background of such important mixtures applied in diverse products and industries, thereby showing a large optimization potential for crystallization technologies.
Vegetable oils and their derivatives are increasingly replacing mineral oils in their applications.[1,2] Among other constituents in vegetable oil, both saturated and unsaturated fractions are important raw materials. The latter possesses double bonds which can provide as substrates or raw materials for various chemical industries.[3] Fractionation of these oils or as in our case the Poly-Unsaturated Fatty Acid (PUFA) mixture is required so as to generate favorable compositions according to applications. Generation of Solid Liquid Equilibrium (SLE) phase diagrams for real mixtures is extremely important to enable a thorough understanding of the thermodynamics of the fractionation process of crystallization. The PUFA mixture was fractionated in a multistage scrubbing layer crystallizer. The product was put into a decanter centrifuge so as to fractionate them into mother liqor and crystal fraction. The temperature in the jacket was maintained such that △T< 5K from the liquidus point obtained from the Differential Scanning Calorimeter (DSC) thermal analyses. Each crystallizer was also maintained at a temperature 5K below the previous one. This way a slow and successive cooling of the PUFA was achieved such that probes from different fraction could be obtained. They were analyzed thermally and chemically in the DSC and Gas Chromatography – Flame Ionization Detector (GC-FID) setup respectively.[4] Similar to previous literature as in [5], technically relevant partial SLE diagrams for high oleic palm oil was created by fractionating the mixture in a scrubbed layer crystallizer along with their metastable range were determined.[6]
The range of application of fatty acids is as broad and varied as the diverse kinds of fatty acids themselves, stretching from bulk scale productions as in the case of biodiesel or lubricant manufacturing over consumer or end products like cosmetics, medicinal or nutritional additives to relatively smaller scale specialty chemicals like epoxy resins, insect repellents and so on. The crystallization temperatures of the unsaturated fatty acids are much lower than those of the saturated ones, which is an important and desirable property for raw materials such as in the production of epoxy resins. Separation and purification of these enriched unsaturated fatty acid fractions depending on their applications is mainly performed by two thermal fractionation processes, namely, distillation and crystallization. The potential behind the success of purification of these multi-component organic fatty acid mixtures with the help of melt crystallization, apart from the fact that it is cost effective owing to the obvious reduction of solvent removal and regeneration steps, is that of the relatively large differences in the melting points of the individual fatty acids.
A detailed and fundamental understanding of the crystallization especially nucleation kinetics of a variety of vegetable oil based fatty acid mixtures has been provided in this work. It also describes the solid-liquid phase diagrams of these poly-unsaturated mixtures including their metastable zone widths of nucleation and solidification. This theoretical part of this thesis is a detailed resource on the global production and application of vegetable oils and their derivatives. A clear mathematical and physical road map for the application of the Fisher Turnbull model to calculate the enthalpy values starting from the very basic supersaturation equation has been established and extensively explained as well. Nucleation studies have been carried out on various reactor setups in micro-, milli- and liter-scale. It successfully models the induction times of nucleation as a function of supercooling at different cooling rates both in micro and macro scale. 3D modeling of this parameter to see the combined effects of temperature and in turn viscosity have also been successfully implemented on the milliliter scale results, as more of the bulk nucleation phenomenon was observed in the latter. Fisher Turnbull plot and the Gibbs Thompsons model were adjusted and applied to correlate the Gibbs free energy, involved with the rate of nucleation captured by the FBRM™ (Focused Beam Reflectance Measurement) technology. The scope of this measurement technology was also tested in liter scale. The results showed that FBRM technology is applicable when the solution is relatively dilute and does not have too many overlapping crystals.
Metal-coated thermoplastic parts find more and more functional and aesthetic applications in the interior and exterior of cars. The vapor-deposited or electroplated coatings are usually composed of a plurality of nickel- and chromium-containing layers, which are applied to copper-containing carrier layers on the polymers. Previously, recycling processes are mainly focussed at the recovery or thermal utilization of the plastics. Targeted and selective recycling of the metallic coatings is usually not carried out.
Together with several SME, BTU developed a process, in which a complete and separate recovery of all components in high purity is possible with biotechnological methods. The bioleaching is carried out with iron and sulfur-oxidizing bacteria, esp. Acidithiobacillus ferrooxidans. The copper-containing layers are dissolved in the solution; chromium- and nickel-containing particles are precipitated as solids. After the bioleaching, a mechanical separation of the individual metal-containing components and their separate workup are carried out. End-products are metallic copper, a nickel- and chromium-containing solid and the cleaned plastics. The bioleaching ensures a high purity of the end products. Through the use of bacteria, which are also found in nature, the process is environmentally friendly. Compared to chemical leaching using inorganic acids, considerably shorter leaching times can be achieved. In addition to the optimization of the leaching process, the R/D-project also includes the development and testing of the apparatus technology.
Due to the European Directive 2000/53/EC on end-of-life-vehicles, from 2015 on more than 95% of car materials have to be recycled. In order to recycle the materials back into the economic cycle, it is necessary to produce products with high quality and purity.
Plastic components in cars, which are coated with metals by vapour deposition or electroplating, have a wide circulation (e.g., as cladding panel or trim strip for interiors and exteriors). In the end-of-life-vehicle recycling process, these plastic-metal composites are not considered in usual technologies (car shredder) and are not separated from Automotive Shredder Residue. These parts can be separated by optical or HF-detection sorting and then introduced to a specific treatment.
Experiments with a specially developed bioleaching configuration showed that the thin coatings, which consist mainly of copper, nickel and chromium, can be removed efficiently from the polymer base materials by a bioleaching solution with Acidothiobacillus ferrooxidans as a leaching agent. The solution used was produced in special fermenters with a 9K-nutrient salt media. During the bioleaching process at 35°C maximum temperature, most of the copper is dissolved and the other metals accumulate as metal sludge. The bacterial cultures based on A. ferrooxidans are robust and resilient.
After a 48-hour bioleaching period while the composites were stirred regularly with ventilation, the plastic particles were completely free from metallic coatings. The metal components are separated for further use: undissolved components (mainly Ni and Cr) are separated by decantation of the solution; dissolved copper recovey is carried out by cementation of copper. The cementated solid contains ~98% Cu, along with small amounts of other metals.
With the bioleaching process, good separation and re-utilization of the metallic coatings is possible. The cleaned plastic parts were prepared by compounding for new applications with injection-moulding.
In this paper, binary phase diagrams of the five main fatty acids present in edible oil based mixtures are shown. While previously the binary systems of one saturated and one unsaturated acid were investigated, in this work the binary mixtures comprise of palmitic (C16:0) and stearic acid (C18:0) or a binary mixture of oleic (C18:1), linoleic (C18:2) or linolenic acid (C18:3). In order to obtain the phase diagrams with all the solid liquid and solid phase transitions, the mixtures were analyzed by means of Differential Scanning Calorimetry (DSC). Phase change boundary functions based on thermodynamic models and experimental values were fitted and compared. The phase diagrams obtained show behaviors in good agreement to literature. The paper contributes to the deeper understanding of the essential phase change effects during industrial crystallization processes.
This study focusses on the production of micro-structured agglomerates with high porosity from iron (III)-hydroxide-containing materials as adsorbent. A fractal structure of the agglomerates was created through a two-stage agglomeration process. Developing porous structures was necessary to increase the adsorption capacity. Various materials were used for the agglomeration experiments: i) filter cake (dry matter content 23 to 27 wt.-%); ii) FerroSorp®DGμ, a product which is already being used commercially for various applications in water cleaning. These materials in the pristine state have different characteristics such as dry matter content and particle size distribution. The desired optimised agglomerates can be achieved with the help of additives or binders, respectively. Additionally, the agglomeration process parameters play a vital role. In order to produce agglomerates with high porosity, the process was carried out in two steps. Firstly, FerroSorp®DGμ (d90 < 30 µm) was agglomerated jointly with the aforementioned filter cake in an Eirich intensive mixer (particle size range 125 µm < d90 < 500 µm). The second agglomeration step post drying was carried out in a pelletisation disc or in an Eirich intensive mixer with the addition of polymeric binders (up to particle sizes ranging from 2 to 4 mm). Agglomerates were characterised both in short and long term loading tests using phosphate as model ion. Contact times were less than 10 min, similar to practical application in percolation columns, or more than 7 days, respectively. The results show that the agglomerates produced in the two-stage pelletisation process have more advantageous properties like better accessibility of the active sites obtained by specificly influencing the particle size distribution during the two-stage pelletisation process.
Naturally occurring plant based fats and oils have a huge potential as renewable resources to synthesize chemically new products apart from being widely used as ingredients in various kind of food and cosmetics. Oils are triglycerides which are basically tri-esters made of glycerol and
three fatty acids. The latter finds application on one hand as raw material for the polymerization of epoxy resins whereas on the other in the manufacturing of biodiesel amongst others. Melt crystallization as a method to enrich a fatty acid mixture with higher unsaturated fractions is
becoming increasingly established. A polyunsaturated fatty acid mixture with high concentration of linolenic acid (C 18:3) was chosen for this work. This linolenic oil fatty acid rich mixture was subjected to different temperature profiles in order to optimize maximum yield of unsaturated fatty acid in the mother liquor post isothermal centrifugal separation. The influence of the temperature profile on the quality of the desired product was thereby investigated. To examine the exact composition of the resulting product several analytical methods like Differential Scanning
Calorimetry (DSC) and Gas Chromatography (GC) were developed and performed. Product compositions with a total saturated content (C16:0 - palmitic acid and C18:0 - stearic acid) of
below 3% was achieved successfully.
This paper reports the study of micro-processes in a novel pre-treatment technique using a pellet forming batch flow vortex reactor of cylindrical shape that consists of axially revolving rotor plates between fixed stator plates. The suspension was first mixed with high molecular weight synthetic polymers by stirring for approximately 50 seconds and then agitated for 20 minutes. The process was optimised for a number of operating conditions including polymer type and dosing regimen, rotation speed, wall-plate gap distance, residence time and suspension filling method. The results of the investigation show that optimising a number of process variables that influence floc formation and growth, along with specific apparatus construction and geometry, help to maintain the suspension in a metastable state that is crucial for the formation of pellet-like compact agglomerates with better dewaterability and uniform aggregate size. A maximum dry solids content of 28.3% after gravity dewatering through a 0.5 mm sieve was recorded during the investigation, with a maximum particle removal efficiency of 97.5%.
The solid liquid phase diagrams of binary mixtures of the five main saturated and unsaturated fatty acids present in most edible plant oils have been determined in this paper. These binary mixtures comprise of a saturated fatty acid, either palmitic (C16:0) or stearic (C18:0) and an unsaturated one, oleic (C18:1), linoleic (C18:2) or linolenic (C18:3) acid. Differential scanning calorimetry (DSC) was used to obtain an overview of the solid liquid transition behaviour including the metastable ranges of these mixtures. In order to describe all the phase transformations in these systems, the boundary functions have been determined and compared. Phase diagrams determined, illustrate characteristic behaviour in accordance to literature. This work specifically focuses on to describe the solid liquid transitions of the mixtures and not on every single transition or reaction. This paper contributes to the elucidation of the phase behaviour of these important mixtures which are applied in diverse industries.
Nucleation kinetics of high linoleic and high oleic polyunsaturated fatty acid (PUFA) mixtures were investigated during melt crystallization by means of an Focused beam reflectance measurement (FBRM) sensor. Samples were analyzed thermally and chemically in the Differential Scanning Calorimeter (DSC) and Gas Chromatograph (GC) respectively. Investigations showed that a high oleic content in the PUFA mixtures lead to higher induction times, τi. Unlike previous investigations, a clear relation between τi and cooling rates was established. τi increases with increasing cooling rates and decreasing supercooling. Activation energies of nucleation, ∆Gc' were determined by means of the Fisher Turnbull equation wherein ∆Gc' decreases exponentially with increasing supercooling. Investigations and further evaluations conclude that while the plot establishes the effect of supercooling on ∆Gc' , it does not incorporate the effects of molecular diffusion or the cooling rate. Hence, 3D modeling was performed to visualize the combined effects of cooling rate and supercooling on induction time.
Characterisation and materials flow management for WEEE plastics from German dismantling centres
(2015)
Enriched plant based unsaturated fatty acid mixtures are increasingly finding applications in various fields like those of production of bio-fuels and polymerization of epoxy resins. In the case of production of epoxy resins, they are highly advantageous due to the presence of multiple double bonds in the fatty acids which provide opportunities for cross linking by substitution. On the other hand, bio-fuels need raw materials with very low crystallization temperatures. This special property can also be attributed to these enriched unsaturated fractions due to their weak inter-molecular interactions owing to the kink in their structures.
Melt crystallization has long been established as an optimal method for purification and enrichment of fractions from mixtures [1,2]. Previous studies have shown promising results with regard to enrichment of unsaturated fractions by melt crystallization processes [1]. Melt crystallization kinetics of two plant based poly-unsaturated fatty acid mixtures have been investigated in this study [3]. A high oleic and a high linoleic fatty acid mixture were chosen for comparison purposes. A V-form reactor was developed for optimal in-situ analysis with the help of the focused beam reflectance measurement (FBRM®, Mettler Toledo Ltd., Switzerland) instrument [3]. Enhanced heat transfer especially to deal with the heat given out during crystallization was enabled through minimal volume of sample, optimized mixing and the special shape of the reactor. Important parameters like induction time, mixing speed, etc have been determined and compared as functions of degree of supercooling and composition of PUFA mixtures. In accordance to theory, the induction times in both the cases decreased with increasing supercooling and mixer speed. On the other hand, the high linoleic fatty acid mixture required much higher supercooling (4.4K to 5.4K) than the high oleic mixture (2.2K to 3.2K) for favorable induction times.
References
[1] S. Dasgupta, N. Dreiack, P. Ay, presented at the 5th Workshop on Fats and Oils as Renewable Feedstock for the Chemical Industry (Eds: J.O. Metzger, M.A.R. Meier), Karlsruhe 2012
[2] G.F. Arkenbout, Melt Crystallization Technology, Technomic Publishing Company Inc., Pennsylvania 1995
[3] S. Xu, Master thesis, Chair of Mineral Processing, Processing of Biogenous Resources, Brandenburg University of Technology, Cottbus 2010
Enriched plant based unsaturated fatty acid mixtures are increasingly finding applications in various fields like those of production of bio-fuels and polymerization of epoxy resins. In the case of production of epoxy resins, they are highly advantageous due to the presence of multiple double bonds in the fatty acids which provide opportunities for cross linking by substitution. On the other hand, bio-fuels need raw materials with very low crystallization temperatures. This special property can also be attributed to these enriched unsaturated fractions due to their weak inter-molecular interactions owing to the kink in their structures.
Melt crystallization has long been established as an optimal method for purification and enrichment of fractions from mixtures [1,2]. Previous studies have shown promising results with regard to enrichment of unsaturated fractions by melt crystallization processes [1]. Melt crystallization kinetics of two plant based poly-unsaturated fatty acid mixtures have been investigated in this study [3]. A high oleic and a high linoleic fatty acid mixture were chosen for comparison purposes. A V-form reactor was developed for optimal in-situ analysis with the help of the focused beam reflectance measurement (FBRM®, Mettler Toledo Ltd., Switzerland) instrument [3]. Enhanced heat transfer especially to deal with the heat given out during crystallization was enabled through minimal volume of sample, optimized mixing and the special shape of the reactor. Important parameters like induction time, mixing speed, etc have been determined and compared as functions of degree of supercooling and composition of PUFA mixtures. In accordance to theory, the induction times in both the cases decreased with increasing supercooling and mixer speed. On the other hand, the high linoleic fatty acid mixture required much higher supercooling (4.4K to 5.4K) than the high oleic mixture (2.2K to 3.2K) for favorable induction times.
The rising applications of enriched unsaturated fatty acid fractions are significantly increasing the need for a cheap method of manufacturing such fractions. Melt crystallization is an established method for purification and enrichment of desired fractions from mixtures [1, 2, 3]. Enrichment of such natural unsaturated fractions by melt crystallization processes has already been proved effective in prior investigations [1, 2]. Since then many analytical and investigative methods have been applied on various natural plant oil based poly-unsaturated fatty acid (PUFA) mixtures to generate the much needed fundamental melt crystallization data [1]. One such method is the use of in-situ polarized light microscopy [1, 4, 5]. Some of the important parameters affecting the melt crystallization of PUFA mixtures are nucleation and crystal growth rate. To be able to observe and visualize these micro-scale phenomena, circular polarized transmitted light microscopy was applied. A tempered chamber (Linkam LS 120) containing the sample between two object slides was placed right within the microscope camera setup (Leica DM RME and Leica DFC 500) with a viewing window. With respect to the transmitted light, the sample was placed between two circular polarized filters such that the system is calibrated for optimal visualization. Unlike linear polarization, in this method every crystal independent of its alignment in the sample, delivers an interference color different from its background. This way, the entire crystal structure could be clearly separated from the melt. Nucleation and crystal growth rate of a high oleic sunflower oil based PUFA was measured using this method at 5K supercooling and 10K/min cooling rate. Growth curves for total crystal area and number of crystals were analyzed and illustrated graphically. A typical S- curve is observed for both the cases starting with a lag phase followed by an exponential growth phase and ending in a saturation phase.
Enrichment of natural unsaturated fractions by melt crystallization processes has already been proved to be effective in prior investigations [1]–[3]. Palmitic, stearic, oleic, linoleic and linolenic acid are the five main fatty acids present in most of these plant based natural oils. There is quite a bit of information about the liquid solid phase behavior of binary mixtures such as palmitic-oleic, stearic-oleic and palmitic-stearic acid mixtures in literature [4]–[6]. Recent investigations have shown phase diagrams of real natural oil based fatty acid systems containing up to 19% saturated content (11% stearic acid and 8% palmitic acid) [7]. Yet, there is hardly any information regarding ternary systems as those of palmitic-stearic-oleic and palmitic-stearic-linoleic acids.
In this work, synthetic mixtures have been used in order to obtain a complete overview of the liquid solid phase diagrams of these ternary mixtures. To imitate naturally occurring mixtures, a mixture with 1:1 ratio of palmitic stearic acid was prepared. Varying amounts of either oleic or linoleic acids were added to this mixture in order to obtain the entire range required for the phase diagrams. These mixtures were then subjected to a specific profile with a wide temperature range in a Differential Scanning Calorimeter (DSC) so as to record every phase transition.
This study successfully concludes that these complex mixtures could be treated as binary mixtures of their saturated and unsaturated contents. This is because there were essentially two main peaks noted in the DSC thermograms. It is to be noted that there was a third peak, assumed to represent the solid transition, in mixtures containing oleic acid. This has already been shown in detail and discussed in prior investigations [6], [7]. Another major discovery was that the solidus line depends on the type of the unsaturated content, that is, the degree of unsaturation, in the mixture.
Important parameters like supercooling and cooling rates affecting the melt crys- tallization of a polyunsaturated fatty acid (PUFA) mixture obtained from sun- flower oil were investigated and compared via high-resolution polarized-light mi- croscopy. PUFA was thermally characterized in a differential scanning calorimeter and the significant liquid-solid-phase transition temperatures determined were then implemented in the development of specific temperature profiles. Analyzed between two glass slides, induction times were found to decrease with low crystal- lization temperatures and the number of nuclei per unit area increased with high- er supercooling and cooling rates. A comparison between the linear crystal growth rates of pure standards of each of the main fatty acids present in the PUFA mixture and the PUFA mixture itself indicated that the latter is much slower than that of each of its pure components.
Multistage melt crystallization of a variety of plant-based polyunsaturated fatty acid (PUFA) mixtures was conducted to obtain an overview on their liquid-solid equilibrium behavior. Crystal fraction and mother liquor samples were analyzed at every stage. Phase behavior diagrams at low saturated fatty acid concentrations were investigated in detail as they are of significant technical relevance with respect to efficient depletion of the saturated content from the samples. A high oleic acid content in the PUFA mixtures led to difficulties in depleting the mother liquor from the saturated content by melt crystallization. Thermograms from the differential scanning calorimetry were supplemented with illustrations which allow a novel interpretation of results and verification of conclusions.
Waste electrical and electronic equipment is a complex waste stream and treatment options that work for one waste category or product may not be appropriate for others. A comprehensive case study has been performed for plastic-rich fractions that are treated in German dismantling centres. Plastics from TVs, monitors and printers and small household appliances have been characterised extensively. Based on the characterisation results, state-of-the-art treatment technologies have been combined to design an optimised recycling and upgrade process for each input fraction. High-impact polystyrene from TV casings that complies with the European directive on the restriction of hazardous substances (RoHS) was produced by applying continuous density separation with yields of about 60%. Valuable acrylonitrile butadiene styrene/ polycarbonate can be extracted from monitor and printer casings by near-
infrared-based sorting. Polyolefins and/or a halogen-free fraction of mixed styrenics can be sorted out by density separation from monitors and printers and small household appliances. Emerging separation technologies are discussed to improve recycling results.
Removal of dyes from effluents by chemical coagulation: Surface charge and particle size aspects
(2003)
New Downstream approaches for highly pure substances and bio fine chemicals from plant materials
(2011)
Agricultural residues as a renewable source of bio-Energy with special focus on cereal straws
(2010)
New quantitative image analysis method for the characterization of mineral and fibrous materials
(2006)
Automatische Sortierung und Möglichkeiten der Verwertung von Kunststoffen aus dem Altfahrzeugbereich
(2005)
Ersatz von Glasfasern
(2004)
Presently the global commodity situation for non ferrous-, precious- and rare metals is characterized by a strong increase in onsumption and a simultaneous shortage of materials derived from primary sources. So the use of secondary raw materials gains is important due to economic and ecological reasons.
Non Ferrous-, precious- and rare earth metals were detected in household waste (Municipal solid waste, MSW) for years. In MSW-treatments plants NF-metals are actually mostly separated from dried fractions. The separation of these metals is carried out with the aim of removing particles which disrupt further processing. A selective enrichment of individual non-ferrous metals has not been carried out previously. The separated fractions contain mixtures of Al, Cu, Zn, Pb, Sn, alloys, precious metals (e. g. Au, Ag, Pt) and rare metals (Ga, In, Nd etc.) along with considerable amounts of contaminations.
The R&D project “NE-Rec” selectively processes the coarsely separated non-ferrous-metal-conglomerates increasing the concentration of targeted metals. Metals and metal mixtures are concentrated by sorting steps and the impurities are discharged from the process. Still contaminated precious metals are then subjected to a wet-chemical treatment. So metals can be specifically brought into solution or can be precipitated to separate unwanted components (inerts, polymers, foreign metals). Further the relevant metals will be concentrated by thermal-metallurgical processes.
The technology, developed in the R&D project, enables identification, separation and processing of non-ferrous metals, precious metals and REM in household waste and transfers them into further processable individual fractions.
Technical realization of the innovative roll-agglomeration of bast fibres in industrial scale
(2014)
The EU Directive 2000/53/EC on end-of life vehicles (ELVs) states that in 2015 at least 85 wt.-% of a vehicle
has to be reused or recycled. This result in the obligatory need to separate additionally metallic and other
components of the automotive shredder residues (ASR), so that they can be professionally prepared for recycling and reuse further. Currently the iron-containing fines of ASR are deposited as it is not possible to process in blast furnaces due to its particle size (< 4 mm), composition and material properties. Additionally problems are also caused in handling and transportation (dust) of the material. This work focuses mainly on the ASR materials utilization in blast furnaces. Material was further separated into two consecutive fractions by carrying out repeated crushing and magnetic separation twice. The two fractions have significantly higher iron content (up to 75 wt.-%) compared to the initial material mixture. The
materials were assessed for their usage in blast furnaces based on the possible pelletisation with and without binders, stability of pellets, shape and size of pellets, etc. Pelletisation of the material was carried out with a single mould pellet press. Further lignite coal was added to the mixture as additive which improved the
pelletisation behavior and the mechanical stability of pellets. Lignite coal was chosen as reducing agent in
the blast furnace process contributing towards additional savings in energy supplied. The experiments reveal that the production of pellets from iron-containing fines is possible with a lignite coal admixture of about 15 wt.-%. These pellets displayed good mechanical stability and can be used in blast furnace processes in recovery of the recyclable metals which are currently not recycled. The recycling of not yet recyclable metals would reduce the deposition and can be easily adopted into the economic cycle by their utilization.
Within the next few years major changes in mobility are expected. Increasing numbers of electric powered cars, electrobikes and E-Scooters define the transport sector. Recently lithium based traction batteries as storage medium have led into matrurity of series production combining high electrical efficiencies with low weights and compact dimensions. Due to the relatively young development with lithium batteries utilization, only few investigation were conducted regarding their recycling. Conventional battery recycling processes can not be applied due to differences in design and chemistry.
So an automated disassembly and processing procedure for lithium traction batteries has been developed in the R/D-project "Li-WERT". Instead of complete smelting of the batteries without pretreatment, an automated disassembly and specific treatment of the material streams was realised, adjusted to the needs of the subsequent recovery technologies. A higher quality, with reduced expenses for the separation of fine-grained or fused material mixes, can be obtained for the individual components. The automated disassembly using an industrial robot significantly reduces dangers for the operating crew.
The selective disassembly and beneficiation allows full recovery of the fractions. The batteries will be disassembled to cell level by the industrial robot. Anodes, cathodes, and separation layers are isolated and processed. The technology is designed, that no waste is generated for disposal. The pelletised cathode coating and the other separated metals (stainless steel, copper, aluminum) can be used in respective metallurgical plants. Circuit boards and plug contacts are also coveted secondary raw materials for reuse.
The process is modular and offers high flexibility, e. g. for new battery types/ sizes by quick adjustment of the robot and tool change. Adaptation to other cathode materials (e. g. Li[FePO]) is possible. After finishing the R/D-project, a pilot plant for demontage was realised in 2013.
The invention relates to a method and device for the continuous production of fiber agglomerates by rolling agglomeration. For the production of an agglomerate, a portion of the fiber material is introduced into a ring-shape roller table which closed on all sides except for an input opening an an output opening. The fiber material portion introduced into the roller table is transported through the roller table by means of a relative movement of two surfaces of the roller table toward each other, the surfaces lying opposite each other. The fiber material is compressed in the roller table and finally discharged from an output opening of the roller table as fiber agglomerate. According to the invitation, the portioning of the fiber material is carried out by the pulling of an amount of fibers out of a stock of corresponding fiber materials is provided on a supply table for each input opening of a roller table, and portions are continously pulled out of said stock by the repeated movement through the sock of carrier means of a pulling device designed therefor and released into the roller table.
Hauptanspruch: Verfahren zur Herstellung von kugelförmigen Gebilden aus Fasern, - indem das Fasermaterial portioniert wird, - die portionierte Menge von Fasern in einem horizontal und vertikal begrenzten kreisförmig ausgebildeten Rollraum auf einem konstanten Umlaufradius einem Rollprozess unterzogen wird, der durch unterschiedliche Relativbewegungen zueinander erzeugende Rotationen einzelner ebener kreisförmiger Bauteile charakterisiert ist und - nach Erreichen einer im Wesentlichen allseitig nahezu runden Form der portionierten Menge von Fasern diese als Rollagglomerat aus dem Rollprozess ausgetragen wird.
Die automobile Antriebstechnik steht in den nächsten Jahrzehnten vor tief greifenden Verän-derungen. Nachdem über 125 Jahre der Verbrennungsmotor die vorherrschende Antriebsart darstellte, basieren neue Entwicklungen auf Elektroantrieben oder auf der Kombination ver-schiedener Antriebsformen. Fahrzeuge mit elektrischen Antrieben haben mittlerweile den Status der Serienreife erreicht und werden perspektivisch zunehmend das Straßenbild be-stimmen.
Mit der so genannten Lithium-Ionen-Traktionsbatterie wurde in den letzten Jahren ein Spei-chermedium zur Serienreife geführt, welches einen hohen elektrischen Wirkungsgrad mit kompakten Maßen und geringem Eigengewicht vereinigt. Mit den auf der Nutzung von Li-thium-Akkumulatoren basierenden Antriebskonzepten kann ein entscheidender Schritt zur Umsetzung einer umfassenden Verbreitung der elektrischen Antriebstechnik im Bereich der individuellen Mobilität erfolgen.